Bone cysts at the meniscal attachment are associated with a longer symptom duration among patients with arthroscopically treated medial meniscus posterior root tear.

PURPOSE: To elucidate the features of bone cysts at attachment sites of medial meniscus posterior root tears (MMPRTs). METHODS: Knees treated using arthroscopic surgery for MMPRT between 2015 and 2022 were retrospectively reviewed. Patients without a memory of onset (painful popping), prior knee surgeries, concomitant ligament or meniscus injuries or fractures were excluded. Duration from onset to magnetic resonance imaging (MRI) and type of tear were evaluated during arthroscopy. On radiography, meniscus signs (cleft/ghost/giraffe neck), bone cysts at the attachment site of the MMPRT and posterior shiny-corner lesions (PSCLs; bone marrow lesions on the meniscal-covered portion of the posterior tibial plateau) were evaluated. The sensitivity and specificity of the bone cysts were assessed by comparison with matched patients who underwent arthroscopic surgery for medial meniscus posterior horn tear. In addition, subgroups (cyst-positive/cyst-negative) among patients with MMPRT were created to assess the features of bone cysts. RESULTS: A total of 275 patients with MMPRT and 275 matched patients with posterior horn tears were evaluated. The sensitivity and specificity of bone cysts for MMPRT in this study were 22.2% and 98.6%, respectively. Among the 275 knees with MMPRT, compared with the cyst-negative group, the cyst-positive group had a longer duration from onset to MRI (12.9 ± 13.1 vs. 8.3 ± 10.9 weeks, respectively, p = 0.025) and reduced occurrence of PSCLs (18.0% vs. 42.0%, respectively, p = 0.031). CONCLUSION: The occurrence of bone cysts at the attachment site was helpful for the accurate diagnosis of MMPRT and related to longer duration from onset to MRI and reduced PSCLs. LEVEL OF EVIDENCE: Level III, cross-sectional study.

Arthroscopic pullout repair versus suture anchor repair for medial meniscus posterior root tear combined with high tibial osteotomy.

BACKGROUND: The aim of this study was to compare the outcomes of pullout repair with a metal button and suture anchor repair for medial meniscus posterior root tears in patients undergoing high tibial osteotomy with varus alignment. METHODS: Patients who underwent arthroscopic pullout repair (P group) and suture anchor repair (SA group) in combination with open-wedge high tibial osteotomy between 2018 and 2021 were retrospectively examined. Patients who received second-look arthroscopy at 1 year and at least 2 years of follow up were included. Structural healing (complete/partial or failed healing) and chondral lesions at the initial surgery and the second-look arthroscopy, radiographic parameters around the knee, Lysholm score, and Tegner activity scale (before and 2 years after surgery) were compared. RESULTS: A total of 88 patients (68 women/20 men, mean age 61.1 ± 7.9 years old) were included in the analysis. Of these, 51 patients underwent pullout repair, while the other 37 underwent suture anchor repair. The SA group showed a significantly higher rate of complete healing (64.9%) than the P group (21.6%, P < 0.001). The Lysholm score significantly improved after surgery in both treatment groups. At the final follow up, the SA group had a significantly higher Lysholm score (89.6 ± 10.7) than the P group (80.9 ± 17.4, P = 0.011). CONCLUSION: Arthroscopic suture anchor repair had superior healing status and Lysholm Score in comparison with pullout repair with a metal button, as it achieved better tension adjustment. This result is meaningful particularly when medial meniscus root repair and high tibial osteotomy are performed simultaneously.

Insufficient restoration of meniscal extrusion by transtibial pullout repair for medial meniscus posterior root tears.

PURPOSE: The long-term changes in the dynamics of the medial meniscus after transtibial pullout repair for medial meniscus posterior root tears (MMPRTs) are not completely understood. Thus, the aim of this study was to investigate the effects of transtibial pullout repair on MMPRTs and whether the effects would be sustained. METHODS: Nineteen knees with MMPRTs that were treated by trans-tibial pullout repair were enrolled in this study. Medial meniscus extrusion (MME) was measured by ultrasonography during knee extension (no weight-bearing with the knee at 0° extension: NW0°) and 90° flexion (no weight-bearing with the knee at 90° flexion: NW90°) with the patient in the supine position and with full weight-bearing (FW0°) preoperatively and at 3 and 12 months postoperatively. The clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score, Lysholm score, and International Knee Documentation Committee score. RESULTS: The difference in MME with NW0° was not statistically significant between the preoperative (3.4 ± 1.0 mm) and 12-month postoperative (3.7 ± 0.6 mm) time points. The MME with NW90° at 3 (2.1 ± 0.7 mm) and 12 months (2.9 ± 0.6 mm) postoperatively were significantly lower than the preoperative values (3.4 ± 0.8 mm) (P < 0.05). However, the value significantly increased from 3 to 12 months postoperatively (P < 0.05). The MME with FW0° at 12 months postoperatively (4.3 ± 0.6 mm) was significantly larger than that at pre-operatively (3.6 ± 0.9 mm) (P < 0.05). All the patients' clinical conditions were significantly improved at 12 months postoperatively when compared to their preoperative clinical conditions. CONCLUSION: Surgery did not reduce the extrusion in the no weight-bearing and weight-bearing positions at knee extension, and these values increased in the postoperative period. In addition, while the surgery reduced the extrusion in the knee flexion position, the restoration achieved by the surgery was not sustained in the long term. LEVEL OF EVIDENCE: Level IV.

Increased Bone Plug Depth From the Joint Increases Tunnel Enlargement in Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Autograft With Suspensory Femoral Fixation.

Purpose: To determine a safe bone plug depth fixation zone based on early tunnel enlargement rates in anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) autograft with suspensory femoral fixation. Methods: Patients who had undergone rectangular tunnel ACL reconstruction using BPTB autograft with suspensory femoral fixation were retrospectively identified. Femoral and tibial tunnel aperture areas were measured on computed tomography 2 weeks and 6 months after surgery to calculate rates of femoral and tibial tunnel enlargement (FTE and TTE), respectively. Femoral bone plug depth (FBPD) and tibial bone plug depth (TBPD) were defined as the distance of the tip of the plug from the respective joint lines. Optimal FBPD and TBPD cutoff values were calculated for the following rates of FTE and TTE, respectively: 0%, 15%, 30%, and 50%. Results: Sixty-four patients (19 females, 45 males; mean age, 29.5 ± 12.3 years) were included in the study. The femoral and tibial tunnel apertures significantly enlarged over time. FBPD (P < .001; r = 0.607) and TBPD (P = .013; r = 0.308) were positively correlated with FTE and TTE, respectively. The optimal FBPD cutoff value was 2.8 mm for FTE rates of 0% and 15%, 3.6 mm for 30%, and 6.0 mm for 50%. The optimal TBPD cutoff value was 1.48 mm for a 0% TTE rate and 5.1 mm for those higher. The cutoff value specificities were lower for the tibial tunnel than the femoral tunnel for each tunnel enlargement rate. Conclusion: Early tunnel enlargement and bone plug depth were significantly correlated in bone the femoral and tibial tunnels. The degree of correlation was higher in the femoral tunnel. To minimize bone tunnel enlargement, the distal end of the femoral bone plug should be placed less than 2.8 mm from the tunnel aperture. Level of Evidence: Level IV, therapeutic case series.

Evaluation of the bone tunnel position and state of healing on second-look arthroscopy after pullout repair of medial meniscus posterior root tear during open-wedge high tibial osteotomy.

BACKGROUND: The aim of the present study was to evaluate the outcome of pullout repair of medial meniscus posterior root tear during open-wedge high tibial osteotomy, including the bone tunnel position and the state of healing on second-look arthroscopy. METHODS: The cohort comprised 22 patients (six men, 16 women) who underwent arthroscopic root fixation by the transtibial pullout technique for medial meniscus posterior root tear during open-wedge high tibial osteotomy. The mean patient age was 63.7 years. The location of the tibial tunnel was assessed using a percentage-dependent method, and the location of a critical point was determined by two coordinates on CT. We defined the distance between the tibial tunnel center and the medial meniscal posterior root anatomic center as the TC-AC distance. The healing state was classified as complete, partial, or failed on second-look arthroscopy. Patients were categorized into those with complete or partial healing (group H) and those with failed healing (group F). The differences in the outcomes and characteristics of groups H and F were evaluated. RESULTS: Twelve and 10 knees were classified into groups H and F, respectively. The bone tunnel position was significantly more posterior in group H than in group F. The TC-AC distance was significantly shorter in group H than in group F. CONCLUSIONS: In pullout repair of medial meniscus posterior root tear during open-wedge high tibial osteotomy, it was considered important to create a bone tunnel position more posterior to increase the healing rate on second-look arthroscopy. LEVEL OF EVIDENCE: Level Ⅳ.

Histological Evaluation of Harvested Specimen of a Patient Who Underwent Unicompartmental Knee Arthroplasty Two Years and Six Months After Medial Meniscus Posterior Root Tear Transtibial Pull-Out Repair.

Transtibial pull-out repair is routinely performed to treat medial meniscal posterior root tear (MMPRT). However, data on the postoperative histological evaluation of the repaired medial meniscus posterior attachment after the procedure is scarce. In this report, we present a histological evaluation of the harvested specimen of a patient who underwent unicompartmental knee arthroplasty (UKA) approximately two years and six months after MMPRT transtibial pull-out repair. The patient was a 75-year-old female. Her X-ray showed Kellgren-Lawrence classification grade II and her MRI revealed MMPRT. Arthroscopic transtibial pull-out repair was performed two months after the onset, and her condition was fine two years after the operation. However, her knee pain gradually worsened, and UKA was performed two years and six months after the initial surgery. The medial meniscus posterior root was continuous from the resected tibia. Tissue specimens were prepared and evaluated. There were Sharpey's fiber-like tissues in the tibial bone tunnel. The medial meniscus posterior attachment showed a four-layer structure of ligaments, uncalcified fibrocartilage, calcified fibrocartilage, and subchondral bone zone. The structures were observed 2,000 ㎛ medially from the bone tunnel. The results revealed that the reconstructed graft after a transtibial pull-out repair for the medial meniscus posterior root showed different histological findings compared with the native posterior root and similar to the anterior root of the medial meniscus.

Sagittal Inclination Angle of Graft Is Associated With Knee Stability After Anatomic Anterior Cruciate Ligament Reconstruction.

PURPOSE: To evaluate whether the sagittal inclination angle (SIA) of a graft is associated with postoperative knee stability after anatomic anterior cruciate ligament (ACL) reconstruction. METHODS: All patients who had undergone anatomic ACL reconstruction between April 2014 and September 2015 in addition to volunteers with no history of knee injury were eligible for inclusion in this study. The patients were evaluated by magnetic resonance imaging of the knee in full extension at 1 year after surgery, as were volunteers. The posterior tibial slope (PTS) angle and the SIA of the intact ACL and reconstructed graft were measured relative to each medial and lateral tibial plateau. The patients were examined for knee stability by the side-to-side difference in the anterior tibial translation on stress radiographs at minimum 2-year follow-up. RESULTS: We included 43 patients (26 male, 17 female, mean age 32.8 ± 14.8 years) and 12 volunteers (7 male, 5 female, mean age 28.7 ± 3.1 years) as normal controls. The mean follow-up duration was 29.8 ± 3.6 months. The mean PTS angle and mean SIA in the patients did not significantly differ from those of the intact ACL. The PTS angle in the patients was not significantly correlated with postoperative side-to-side difference in the anterior tibial translation. However, the graft SIA was significantly correlated with the postoperative anterior tibial translation (medial SIA; r = 0.42, P = .005, lateral SIA; r = 0.52, P < .001). CONCLUSIONS: Even if anatomically reconstructed, the graft SIA in reference to the tibial plateau at full knee extension is variable and is associated with postoperative knee stability. The larger graft SIA was correlated with graft laxity after anatomic ACL reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Association between postoperative meniscal extrusion and clinical outcomes of the pullout fixation technique for medial meniscus posterior root tear.

OBJECTIVE: To evaluate the correlation between meniscal extrusion in the coronal plane with clinical and radiological outcomes at a minimum of 1 year after transtibial pullout fixation for medial meniscus posterior root tear (MMPRT). METHODS: Data from 30 patients (five males, 25 females) with MMPRT who underwent arthroscopic root fixation by the transtibial pullout technique between 2011 and January 2015 were retrospectively analyzed. The mean patient age was 60.7 ± 8.3years. The median time between injury and surgery was 3.8 months (range, 0.5-15 months). Medial meniscus radial displacement was assessed on magnetic resonance imaging performed preoperatively and at 1 year after fixation. The patients were divided into two groups based on the presence on magnetic resonance imaging of decreased meniscal extrusion (group A) or increased meniscal extrusion (group B) at 1 year postoperatively compared with preoperatively. The two groups were compared regarding factors including age at surgery, sex, body mass index, time between injury and surgery, and the Lysholm score and Kellgren-Lawrence (K-L) grade preoperatively and at 1 year postoperatively. RESULTS: There were seven knees in group A, and 23 in group B. Both groups had a significantly improved Lysholm score postoperatively compared with preoperatively (p < 0.001). Although the postoperative K-L grade was significantly worse than the preoperative K-L grade in group B (p < 0.001), the postoperative K-L grade did not worsen postoperatively in group A. CONCLUSION: The K-L grade did not worsen postoperatively in the group with decreased meniscal extrusion at 1 year after transtibial pullout fixation for MMPRT compared with preoperatively.

A steep coronal graft bending angle is associated with bone tunnel enlargement of the posterolateral bundle after anterior cruciate ligament reconstruction.

PURPOSE: The correlation between the graft bending angle (GBA) of the anteromedial bundle and posterolateral bundle after anterior cruciate ligament reconstruction (ACLR) and postoperative tunnel enlargement was evaluated. METHODS: Two hundred fifty-eight patients (137 males, 121 females; mean age 27.3 years) who had undergone double-bundle ACLR were included. Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months postoperatively. The area of the tunnel aperture for femoral anteromedial tunnel (FAMT) and femoral posterolateral tunnel (FPLT) was measured; the area at 2 weeks after ACLR was subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. The femoral tunnel angles were obtained with Cobb angle measurements. The femoral tunnel angle in the coronal plane was measured relative to the tibial plateau (coronal GBA). On the median value, the patients were divided into two groups in each of FAMT and FPLT; those with a coronal GBA of FAMT of ≥27° were classified as group A, while those with a coronal GBA of <27° were classified as group B, those with a coronal GBA of FPLT of ≥23° were classified as group C, while those with a coronal GBA of<23° were classified as group D. RESULTS: Group A included 129 knees, while group B included 129 knees. Groups A and B did not significantly differ regarding FAMT enlargement. Group C included 133 knees, while group D included 125 knees. The percentage of FPLT enlargement in group C was significantly smaller than that in group D (p = 0.001). CONCLUSIONS: A steep coronal GBA of the FPLT after ACLR results in greater FPLT enlargement. The present findings suggest that surgeons should avoid creating a steep GBA of the FPLT in the outside-in technique.

The relationship between the clinical results and the remnant type following anterior cruciate ligament reconstruction using a hamstring tendon.

PURPOSE: The aim of the present study was to investigate the correlations among the preoperative and postoperative knee laxity, the clinical results, and the type of remnant tissue following the anterior cruciate ligament (ACL) reconstruction. METHODS: One hundred ninety-two patients (male, n = 101; female, n = 91; mean age, 27.1 years) with ACL-deficient knees who had undergone double-bundle reconstruction were included. The time between injury and surgery (TBIS) was 34.7 weeks (range, 1-504 weeks). The subjects were divided into four groups according to the Crain's classifications and factors such as the age at surgery, gender, TBIS, side-to-side difference (SSD), Tegner activity score (TAS), and Lysholm score were compared. RESULTS: The percentage of patients with ACL remnant pattern types 1, 2, 3, 4 was 19% (37 knees), 52% (101 knees), 9% (19 knees), and 18% (35 knees), respectively. The TBIS of the patients with Crain type 4 was significantly longer in comparison to the other groups ( p < 0.01). A significant difference was observed in the preoperative SSD of the Crain type 3 and Crain type 4 (6.2 ± 3.4 mm, 9.3 ± 3.6, respectively) groups. The TBIS in patients with Crain type 4 was significantly longer in comparison to the other groups ( p < 0.01). There were no significant differences between the groups in terms of the postoperative SSD, TAS, or Lysholm score. CONCLUSION: This study suggests that a Crain type 3 remnant was associated with a significantly lower preoperative SSD. In addition, the TBIS in patients with Crain type 4 was found to be significantly longer in comparison to the other groups. LEVEL OF EVIDENCE: Level III, case-control study.

The Effect of Remnant Tissue Preservation in Anatomic Double-Bundle ACL Reconstruction on Knee Stability and Graft Maturation.

Several investigators have developed anterior cruciate ligament reconstructions (ACLR) with remnant tissue preservation (RTP) and have reported better clinical outcomes. However, the effects of RTP remain controversial. To date, no reports have compared both clinical and radiological outcomes of anatomic double-bundle ACLR using the hamstring tendon and outside-in technique with/without RTP. This article evaluates the effectiveness of RTP in ACLR on knee stability and graft maturation. In total, 75 patients with unilateral ACL injury who had undergone anatomic double-bundle ACLR using autografted hamstring tendon either with RTP (Group P, n = 43) or without (Group N, n = 32) were enrolled. Clinical scores, pre- and postoperative side-to-side differences (SSDs) obtained using Telos, radiological evaluations of the grafted tendon using the signal/noise quotient (SNQ) measured using magnetic resonance imaging, and arthroscopic evaluations of the grafted tendon were retrospectively compared between the groups. Postoperative SSDs were smaller in the Group P (0.78 ± 1.90 mm) than in the Group N (1.29 ± 2.18 mm); however, this difference was not significant. Comparing two subgroups of the Group P, the SSD was significantly smaller in those with sufficient remnant coverage (-0.56 ± 1.38 mm) than in those without (1.48 ± 1.77 mm) (p = 0.019), as well as in the Group N patients (p = 0.019). The degree of synovial coverage of the anteromedial (p = 0.0064) and posterolateral (p = 0.032) bundle grafted tendon at the time of second-look arthroscopy was significantly better in the Group P than in the Group N. SNQ values of ACL grafted tendon at proximal (p = 0.049), middle, and distal (p = 0.039) one-third in Group P were better than those in Group N. RTP may enhance synovial coverage and maturation of the grafted tendon. Sufficient remnant tissue coverage may contribute to better knee stability. This is a Level III, retrospective comparative study.

The remnant preservation technique reduces the amount of bone tunnel enlargement following anterior cruciate ligament reconstruction.

PURPOSE: The aim of the present study was to investigate the correlation between postoperative tunnel enlargement after ACLR and remnant tissue preservation using the hamstring tendon. METHODS: One hundred and ninety-two subjects (male, n = 101; female, n = 91; mean age 27.1) who had undergone double-bundle ACL reconstruction were included in the present study. The patients were divided into two groups: the remnant tissue preservation group (Group R) and the non-remnant tissue preservation group (Group N). Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture for the anteromedial femoral tunnel (FAMT), posterolateral femoral tunnel (FPLT), anteromedial tibial tunnel (TAMT), and posterolateral tibial tunnel (TPLT) was measured. The area at 2 weeks after ACLR was subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. The differences in the outcomes and characteristics of the two groups were evaluated. RESULTS: Seventy-seven knees were classified into Group R, and 115 knees were classified into Group N. The age, gender, and body mass index did not differ to a statistically significant extent. The percentages of FAMT and TAMT enlargement in Group R were significantly smaller in comparison with Group N (P = 0.003 and P = 0.03, respectively). The percentage of FPLT and TPLT enlargement in the two groups did not differ to a statistically significant extent. CONCLUSION: The remnant-preserving technique reduces the amount of bone tunnel enlargement. The present findings indicate the advantages of the remnant-preserving ACLR technique, and therefore the remnant-preserving technique should be recommended. LEVEL OF EVIDENCE: II.

Patient age as a preoperative factor associated with tunnel enlargement following double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts.

PURPOSE: A few studies have detected associations of post-operative tunnel enlargement with sex, age, and the timing of anterior cruciate ligament reconstruction (ACLR). The aim of the present study was to investigate the correlation between post-operative tunnel enlargement following ACLR using hamstring tendon autografts and preoperative factors. The authors hypothesized that tunnel enlargement is associated with age in patients undergoing ACLR. METHODS: One hundred and six patients (male, n = 57; female, n = 49; mean age, 26.9 years) who underwent double-bundle ACL reconstruction were included in the present study. The time between injury and surgery was 26.3 ± 71.4 weeks. Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture was measured for the femoral anteromedial tunnel (FAMT), femoral posterolateral tunnel (FPLT), tibial anteromedial tunnel (TAMT), and tibial posterolateral tunnel. The percentage of tunnel area enlargement was defined as the area at 2 weeks after ACLR subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. Spearman's correlation coefficient was calculated for each factor. The patients were divided into two groups based on age. Patients aged <40 and ≥40 years were assigned to Groups A and B, respectively. The differences in the outcomes and characteristics of the two groups were evaluated. RESULTS: The percentage of enlargement of the FAMT, FPLT, and TAMT was correlated with patient age (r = 0.31, p = 0.001; r = 0.24, p = 0.012; and r = 0.30, p = 0.002, respectively). In total, 87 and 19 knees were classified into Groups A and B, respectively, based on patient age. The percentage of enlargement of the FAMT was significantly higher in Group B than A (78 vs. 60%, respectively; p = 0.01). The percentage of enlargement of the TAMT was significantly higher in Group B than A (53 vs. 36%, respectively; p = 0.03). CONCLUSION: The percentage of enlargement of the FAMT and TAMT was associated with patient age. These findings suggest the need to consider the possibility of tunnel enlargement when double-bundle ACLR is performed for patients aged >40 years. Age was a preoperative factor associated with tunnel enlargement. LEVEL OF EVIDENCE: III.

Factors affecting knee laxity following anterior cruciate ligament reconstruction using a hamstring tendon.

BACKGROUND: The aim of the present study was to investigate the correlation between the pre-operative and intraoperative factors that predict postoperative knee laxity following anterior cruciate ligament (ACL) reconstruction using a hamstring tendon. METHODS: The subjects included 108 patients (male, n=49; female, n=59) with ACL-deficient knees who had undergone double-bundle reconstruction. The median time between injury and surgery (TBIS) was 27.5weeks (range one to 504). The patients were divided into two groups according to the side-to-side difference (SSD) in anterior translation on a stress radiograph one year after undergoing the operation (Group A: SSD of <3mm and Group B: SSD of ≥3mm) and were compared regarding such factors as age at surgery, sex, body mass index, pivot shift test, TBIS, pre-operative laxity, concomitant ligament, meniscus, and articular cartilage injury. A logistic regression analysis was performed to identify the factors associated with knee laxity. RESULTS: The postoperative SSD values after one year were correlated with the TBIS (r=0.28; P<0.01). Eighty-one and 27 knees were classified into Groups A and B, respectively, based on the SSD at one year after surgery. The TBIS in Group B (60.2weeks) was significantly longer than that in Group A (16.6weeks; P<0.01). A logistic regression analysis showed that there was a significant association between the TBIS and postoperative knee laxity (P<0.01; odds ratio 1.013; 95% CI 1.002-1.023). CONCLUSION: Increased knee laxity was associated with the time between injury and surgery.

Tibial Tubercle in Valgus Osteoarthritic Knees Is More Laterally Positioned Than in Varus Knees.

BACKGROUND: The tibial tubercle (TT) is the most reliable landmark of the tibial component rotation in total knee arthroplasty. However, there is no report comparing the position of the TT between valgus and varus osteoarthritic knees. METHODS: Using preoperative computed tomography, we measured the TT-posterior cruciate ligament (PCL) distance representing the degree of lateralization of the TT and the angle between Akagi's anteroposterior (AP) axis and the dorsal condylar line (DCL) of the tibia in 36 valgus and 40 varus osteoarthritic knees and compared them. RESULTS: The mean TT-PCL distances in valgus and varus knees were 26.1 (18.2-36.8) and 17.2 mm (10.3-22.6), respectively, with a significant difference (P < .001). Twenty-four of 36 valgus knees (67%) had abnormal TT-PCL (>24 mm). The mean AP-DCL angles in valgus and varus knees were 103° (95.8°-114.8°) and 93.2° (85.3°-99.6°), respectively, with a significant difference (P < .001). CONCLUSION: The TT in valgus knees was significantly more laterally positioned than in varus knees. Also, Akagi's AP axis in valgus knees was significantly more externally rotated relative to the DCL of the tibia than in varus knees. Attention is necessary to correct rotational alignment without posterolateral overhang of the tibial component during total knee arthroplasty, particularly for valgus knees.

Clinical Outcomes After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Comparison of Extreme Knee Hyperextension and Normal to Mild Knee Hyperextension.

PURPOSE: The aim of this study was to compare postoperative outcomes after anatomic double-bundle anterior cruciate ligament reconstruction (ACLR) in extreme knee hyperextension versus normal to mild knee hyperextension. METHODS: For 100 patients who underwent anatomic double-bundle ACLR using semitendinosus tendon, we evaluated the side-to-side difference (SSD) in anterior tibial translation (measured on stress radiographs) and rotational stability (assessed by the pivot-shift test) 2 years after surgery. Loss of extension (LOE) was evaluated on lateral radiographs of both knees in full extension, and graft integrity was assessed during second-look arthroscopy 1 to 2 years after surgery. In accordance with the Beighton and Honan criteria, patients with an extension angle less than or equal to 10° in the contralateral uninjured knee composed the group with 10° or less hyperextension (N group), and those with an extension angle of greater than 10° composed the group with more than 10° hyperextension (H group). Postoperative results were compared between these groups. RESULTS: Mean extension angles in the N and H groups were 5.8° ± 2.9° and 14.7° ± 3.0°, respectively. The mean SSD in anterior translation was 2.2 ± 2.9 mm for the N group and 2.8 ± 2.9 mm for the H group, with no significant difference. The positive ratios on the pivot-shift test were not significantly different between the groups. Mean LOE in the N and H groups was -0.7° ± 3.7° and 1.3° ± 3.3°, respectively, with a significant difference (P = .007). During second-look arthroscopy, 6 of 58 knees in the N group and 13 of 42 knees in the H group had superficial graft laceration of the anteromedial bundle graft, with a significant difference (P = .01) seen between groups. CONCLUSIONS: Anatomic double-bundle ACLR for extreme knee hyperextension may attain the same postoperative anterior and rotational stability as seen in knees with normal to mild hyperextension. However, it increased superficial graft laceration. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Immunolocalization of water channel aquaporins in human knee articular cartilage with intact and early degenerative regions.

Aquaporins (AQPs), a family of water channel proteins expressed in various cells and tissues, serve as physiological pathways of water and small solute transport. Articular cartilage is avascular tissue with unique biomechanical structure, a major component of which is "water". Our objective is to investigate the immunolocalization and expression pattern changes of AQPs in articular cartilage with normal and early degenerative regions in the human knee joint, which is the joint most commonly involved in osteoarthritis (OA). Two isoforms (AQPs 1 and 3) of AQPs were examined by immunohistochemical analyses using isoform-specific antibodies with cartilage samples from OA patients undergoing total knee arthroplasty. AQP 1 and AQP 3 were expressed in human knee articular cartilage and were localized in chondrocytes, both in the intact and early degenerative cartilage regions. Compared to the intact cartilage, both AQP 1 and AQP 3 immunopositive cells were observed at the damaged surface area in the degenerative region. These findings suggest that these AQPs play roles in metabolic water regulation in articular cartilage of load bearing joints and that they are responsible for OA onset.

The outcomes after anterior cruciate ligament reconstruction in adolescents with open physes.

PURPOSE: We evaluated the clinical outcome of anterior cruciate ligament reconstruction (ACLR) in adolescents with open physes and compared those results with adults. MATERIALS AND METHODS: Fifteen adolescents with open physes underwent physeal-sparing double-bundle ACLR using hamstring autograft. The median age of the adolescents was 14 years (range 13-16 years). Forty adults underwent anatomic double-bundle ACLR during the same period of this study. The median age of the adults was 26 years (range 17-39 years). Clinical outcomes were evaluated in terms of manual Lachman test, pivot shift test and the results of KT-2000 arthrometer. Additionally, we evaluated clinical outcome in terms of International Knee Documentation Committee (IKDC) score and Lysholm Knee Scoring Scale. We also evaluated rates of re-rupture. RESULTS: No clinically significant growth abnormalities were observed in adolescent cases. In the Lachman test, two of the 15 adolescents had a positive, whereas one of the 40 adults had a positive (n.s.). In the pivot shift test, three of the 15 adolescents had a positive, whereas two of the 40 adults had a positive (n.s.). There was no statistically significant difference between adolescents and adults, in the mean side-to-side difference in KT-2000 measurements (1.5 ± 1.5 mm vs. 1.1 ± 1.9 mm: n.s.), the median IKDC score (96.7 vs. 97.3: n.s.) and Lysholm Scale (99 vs. 98: n.s.), rates of re-rupture (13.3 vs. 7.5 %: n.s.). CONCLUSION: Physeal-sparing ACLR with hamstring autograft in adolescents with open physes resulted in good clinical outcomes similar to those of ACLR in adults without growth abnormalities.

Clinical and second-look arthroscopic study comparing 2 tibial landmarks for tunnel insertions during double-bundle ACL reconstruction with a minimum 2-year follow-up.

BACKGROUND: Few studies have reported the clinical results of tibial tunnel placement during double-bundle anterior cruciate ligament (ACL) reconstruction. It is important to recognize arthroscopic tibial landmarks during this procedure. HYPOTHESIS: During arthroscopic double-bundle ACL reconstruction, anterior tibial landmarks such as the intermeniscal (transverse) ligament and the Parsons knob for the anteromedial (AM) tunnel provide better knee stability and clinical outcomes than do posterior tibial landmarks such as the fovea anterior to the tibial intertubercle ridge for the posterolateral (PL) tunnel. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 121 patients underwent primary unilateral double-bundle ACL reconstructions using autogenous medial hamstring tendons. Fifty-nine patients from December 2008 through July 2009 underwent reconstructions using posterior tibial landmarks (PL group), and 62 patients from August 2009 through February 2010 underwent reconstructions using anterior tibial landmarks (AM group). Forty-seven patients (follow-up rate, 79.7%) in the PL group and 52 patients (follow-up rate, 83.9%) in the AM group underwent second-look arthroscopy and clinical evaluations under anesthesia at 1 year postoperatively and 3-dimensional computed tomography (3-D CT) evaluations at 3 weeks postoperatively. RESULTS: Lachman test results indicated no significant differences, and pivot-shift test results were significantly lower in the AM group (P = .007). Mean side-to-side differences using the Telos device at 130 N were significantly lower in the AM group (1.4 ± 1.6 mm) compared with the PL group (2.4 ± 2.5 mm) (P = .012). Results for lack of extension were not significantly different, while those for lack of flexion were significantly better in the AM group than in the PL group (P = .036). No significant differences were observed in the Lysholm scores between the groups. In measurements of the tibial tunnel position by 3-D CT, with regard to anteroposterior depth, the AM bundle of the PL group was 41.6% ± 7.4% and the AM group was 29.1% ± 5.3% (P < .001), and the PL bundle of the PL group was 55.6% ± 7.7% and the AM group was 46.4% ± 5.8% (P < .001). No significant differences were found in mediolateral width. In second-look arthroscopy, there were significant differences with respect to the synovial cover with regard to the AM bundle (P = .024). CONCLUSION: Patients in the AM group showed better knee stability and range of motion than those in the PL group. Transverse ligaments and Parsons knobs proved to be useful landmarks during ACL reconstruction.